Unauthorized wireless use is a major problem in restricted areas. The problem is particularly exacerbated in restricted areas in which telecommunication can lead to illicit activities or can cause harm to wireless user or third party. Various issues can originate from unauthorized wireless use. Using short message service (SMS), prisoners in correctional facility may control illegal outside activities. Accessing messaging applications in mobile device may enable students to misrepresent knowledge or ability in examinations. Industrial or governmental spies may collect and deliver classified or proprietary information. Air controller that diverts attention from control activities to attend to cellphone call may cause aircraft collision with possible loss of life. Inconsiderate wireless users may disturb others in confined settings such as a theater, a church, a library, or the like.
To mitigate unauthorized wireless communication in restricted areas, typically adopted solutions relay primarily on negation of wireless resources (e.g., electromagnetic spectrum bandwidth) through deliberate spectral interference; such solutions are commonly known as radio jamming. Even though radio jamming is widely available and employed, it generally displays a number of utility inefficiencies: (1) Lack of spectral selectivity. For a specific block of EM spectrum, all radio frequencies, users, and calls sessions including emergency (e.g., E911) calls are blocked. The latter may lead to safety issues for users in the restricted areas. (2) Inability to allow for user tracing or location. Radio jammed calls cannot be traced or located. (3) Substantial implementation costs. Conventional radio jamming exploits considerable, expensive equipment and consumes significant power to negate wireless resources in wide blocks of EM spectrum. Such inefficiencies typically result in inadequate solutions for preventing unauthorized wireless communication in restricted areas.